<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    Promise.resolve().then(()=> {
      console.log(0);
      return Promise.resolve(4)
    }).then((res) => {
      console.log(res);
    })

    Promise.resolve().then(()=> {
      console.log(1);
    }).then(() => {
      console.log(2);
    }).then(() => {
      console.log(3);
    }).then(() => {
      console.log(5);
    }).then(() => {
      console.log(6);
    })
    // 0,1,2,3,4,5,6
  </script>
</body>
</html>